Added 'therubyracer' dependency to the assets group
Move js tests to `test/javascripts`
Latest ember
Latest ember-data
Introduce Sinon.js for spies, stubs and mocks
Defer App readiness until application view has loaded.

This provides finer control over readiness for testing.
Convert mocha tests to be client-side integration tests
Set`Ember.testing = true` in tests.

This prevents automatic scheduling of runloops. We also need to set `App.isInitialized = true;` to prevent `App.initialize()` from being scheduled. This probably shouldn't be necessary and should be addressed in Ember itself.
Minor test cleanup
Remove useless 'arrangedContent'. The controller it itself sorted
Improve runloop usage in tests
Remove defer/advanceReadiness
Latest ember
Utilize new App readiness promise to improve app initialization / reset logic
Defer App readiness immediately upon creation.

Advance App readiness as appropriate for tests vs. production.

Also, fix a mixup of initialized vs. ready in tests.